SEOUL, Dec. 14 (Yonhap) -- Lockheed Martin Corp. can deliver F-35 fighter jets as early as 2016 if it wins South Korea's multi-billion dollar contract for a fighter modernization program, a senior company executive said Tuesday, dismissing doubts over a delay in the new warplane's flight-test schedule.

South Korean officials say the cost rise for an individual F-35 aircraft, stemming from the delay, is a potential obstacle for Lockheed in an upcoming tender by Seoul for 60 fighter jets, valued at 9.7 trillion won (US$8.5 billion).

Seoul is expected to invite bidders as early as next year for the third stage of the fighter modernization program to replace aging F-4E and F-5E/F jets that have been involved in several deadly crashes in recent years. The delivery of new aircraft is scheduled to start in 2016.

The delay in the flight-test schedule, however, would force South Korea to buy F-35s after 2018 if it selects Lockheed, South Korean officials said. Lockheed, Boeing Co. and a consortium of European firms led by EADS have expressed interest in the tender.

"We are confident in our ability to deliver aircraft to the Republic of Korea (South Korea) Air Force beginning as early as 2016," Steve O'Bryan, Lockheed's vice president for F-35 business development, said in an interview with Yonhap News Agency.

"While the F-35 program has experienced some cost growth in the development portion of the program, the cost will not be passed on to international customers," O'Bryan said.

South Korea has purchased 60 of Boeing's F-15 fighter jets under the first two stages of the fighter modernization program, code-named "F-X," since 2002.

Lockheed's F-35 Lightening II Joint Strike Fighter, Boeing's newly-designed F-15 Silent Eagle and the Eurofighter Typhoon made by the European consortium are likely to compete for the third-stage order, according to officials at South Korea's arms procurement agency.

South Korea buys most of its military weapons from the United States, which maintains 28,500 troops in the South, a legacy of the 1950-53 Korean War.

Officials at the South's Defense Acquisition Program Administration, the agency in charge of the F-X program, said they will make technology transfer one of the top priorities in the upcoming tender, so it is important to produce fighter jets with basic stealth capabilities.

O'Bryan said the F-35 would be advantageous in this context.

"The unique opportunities that exist on the F-35 program from an industrial perspective allow a country's industries to recapitalize their capabilities at the same time their air force recapitalizes with the next generation of fighter aircraft," he said.

The U.S. government is the main customer and financial contributor for Lockheed's F-35 program, valued at more than $300 billion. Also, eight countries, including Britain, Canada and Turkey, are taking part in the largest weapons program in history by shouldering some development costs.

O'Bryan said Israel recently signed a preliminary deal to buy the first batch of F-35s, marking the first foreign sale of the new warplanes.

"Israel, like Korea is faced with a multitude of security challenges," O'Bryan said, "The fact that Israel has decided to move forward with the F-35 procurement is an indication that the F-35 Lightening II brings an entirely new level of capability to the warfighter."